The present invention relates generally to ophthalmic lenses, and more particularly to accommodative intraocular lenses (IOLs) exhibiting dynamic aberrations.
The optical power of the eye is determined by the optical power of the cornea and that of the crystalline lens, with the lens providing about a third of the eye's total optical power. The lens is a transparent, biconvex structure whose curvature can be changed by ciliary muscles for adjusting its optical power so as to allow the eye to focus on objects at varying distances. This process is known as accommodation. As a result of accommodation, spherical aberration exhibited by the natural lens shifts in the negative direction.
The natural lens, however, becomes less transparent in individuals suffering from cataract, e.g., due to age and/or disease, thus diminishing the amount of light that reaches the retina. A known treatment for cataract involves removing the opacified natural lens and replacing it with an artificial intraocular lens (IOL). Although such IOLs can improve the patient's vision, they can, however, lead to the loss, or at least severe curtailment, of the eye's accommodative ability. In particular, a class of IOLs, commonly referred to as monofocal IOLs, provide a single optical power and hence do not allow accommodation. Another class of IOLs, commonly known as diffractive IOLs, provide primarily two optical powers, typically a far and a near optical power. As such, these IOLs provide only a limited degree of accommodation, commonly known as pseudoaccommodation.
Dual-optic accommodative IOLs are also known that utilize the movement of two optical elements relative to one another in response to the movement of the ciliary muscles to provide a degree of continuous accommodation. However, the range of movement of the two optics of such IOLs is typically limited, thus restricting the range of viewing distance over which they provide accommodation.
Accordingly, there is a need for enhanced IOLs, and particularly improved accommodative IOLs as well as for methods of correcting vision that utilize them.